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File: classes/parser/parser.php

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  Classes of Gonzalo Chumillas  >  PHP CSS Parser  >  classes/parser/parser.php  >  Download  
File: classes/parser/parser.php
Role: Class source
Content type: text/plain
Description: Parser class
Class: PHP CSS Parser
Get HTML document nodes matching a CSS selector
Author: By
Last change:
Date: 2 years ago
Size: 2,930 bytes
 

Contents

Class file image Download
<?php
/**
 * This file contains the Parser class.
 *
 * @author Gonzalo Chumillas <gonzalo@soloproyectos.com>
 * @package parser
 */
require_once dirname(__DIR__) . "/parser/exceptions/parser-exception.php";
require_once
dirname(__DIR__) . "/parser/tokenizer.php";

/**
 * class Parser
 * Parses a string.
 */
abstract class Parser extends Tokenizer {
   
/**
     * This flag indicates that we want to perform a "non-greedy" analysis.
     */
   
const UNGREEDY = 0x4;
   
   
/**
     * @var string|Parser
     */
   
private $target;
   
   
/**
     * Flags.
     * @var int
     */
   
private $flags;
   
   
/**
     * @param string|Parser $target
     * @param int $flags = 0
     */
   
public function __construct($target, $flags = 0) {
       
$this->target = $target;
       
$this->flags = $flags;
       
        if (
$this->target instanceof Parser) {
           
parent::__construct($target->getString(), $flags);
           
$this->offset = $target->getOffset();
        } else {
           
parent::__construct($target, $flags);
        }
    }
   
   
/**
     * Parses a string.
     * @return mixed
     */
   
abstract protected function _parse();
   
   
/**
     * Tries to parse a string and throws an exception if unsuccessful.
     * This is the habitual use of the parser method:
     *
     * <code>
     * $p = new MyCustomParser($string);
     * $info = $p->parse();
     * if (!$info) {
     * echo "Invalid expression";
     * }
     * </code>
     *
     * @throws Exception
     * @return mixed
     */
   
public function parse() {
       
$ungreedy = Parser::UNGREEDY & $this->flags;
       
$ret = $this->_parse();
       
        if (
$ret) {
            if (
$this->target instanceof Parser) {
               
$this->target->setOffset($this->offset);
            } else
            if (!
$ungreedy && !$this->end()) {
                throw new
ParserException($this, "Unrecognized expression");
            }
        }
       
        return
$ret;
    }
   
   
/**
     * Matches the string against a function and moves the offset forward if the function returns TRUE.
     * @param string $method_name Method name
     * @param array $args Additional arguments
     * @throws Exception
     * @return mixed
     */
   
protected function is($method_name, $args = NULL /* ... additional arguments */) {
        if (!
method_exists($this, $method_name)) {
            throw new
Exception("The method `$method_name` does not exist");
        }
       
        if (!
is_callable(array($this, $method_name))) {
            throw new
Exception("The method `$method_name` is inaccessible");
        }
       
       
$offset = $this->offset; // saves offset
       
$ret = call_user_func_array(array($this, $method_name), array_slice(func_get_args(), 1));
        if (!
$ret) {
           
$this->offset = $offset; // restores offset
       
}
       
        return
$ret;
    }
}